Prior art container closures having a pour spout or the like are disclosed in U.S. patent application Ser. No. 08/332,140 filed Oct. 31, 1994 (now U.S. Pat. No. 5,588,562) which is the priority document for International Patent Application No. PCT/IB95/01105 (published May 9, 1996 under International Publication No. WO 96/13442), U.S. patent application Ser. No. 08/633,225 filed Apr. 16, 1996 (abandoned), U.S. patent application Ser. No. 08/687,149 filed Jul. 24, 1996 (now U.S. Pat. No. 5,862,953), U.S. patent application Ser. No. 08/838,133 filed on Apr. 15, 1997, and U.S. Pat. Nos. 5,104,008 and 5,465,876. Such prior spout closures provide tamper evidency and have tamper evident pour spouts but have not been leak proof at the spout closure interface. Generally, prior art push-pull spouts that are reusable do not provide effective sealing at the juncture between the spout opening and the plug positioned in the opening when the spout is closed. Because of the very small diameter of the opening and the concern for safety, it is not possible to add non-integrated sealing means. The present invention solves this problem by utilizing a closure plug which combines a circular closure disk with an integral annular skirt depending from the periphery of the disk thereby defining a hollow cavity for the plug interior and increasing the structural flexibility of the plug. The increased structural flexibility provided by the hollow cavity causes inward deformation of the plug skirt upon engagement with annular flanges integrated into the periphery of the spout closure central opening to create a form-fitting leak tight seal. A plurality of circumferentially spaced dimples optionally extend from the exterior wall of the pour spout. These dimples facilitate breaking the frangible elements connecting the tamper evident band to the push-pull pour spout closure. Optionally, one or more continuous or discontinuous locking beads on the pour spout can be configured to engage one or more continuous or discontinuous locking beads on the pour spout closure to provide a structure for securing the pour spout closure to the pour spout the closed position and/or to prevent removal of the pour spout closure from the pour spout in the open position.
The present invention also optionally provides a dust cover which encloses the push-pull pour spout closure when inserted on the container. One example of the use of dust covers as a means for sealing containers is shown in U.S. Pat. No. 5,456,374. The dust cover of the present invention is optionally provided with a tamper-evident sealing band which remains intact upon initial installation of the dust cover onto the container and which is broken when the dust cover is initially disturbed. The purpose of the dust cover is to provide an indication of whether the push-pull pour spout closure has been exposed subsequent to the sealing of the container. When the dust cover is provided with a tamper-evident sealing band, the use of a band on the lower edge of the pour spout closure for providing tamper-evidency may be eliminated.
Snap-on tamper evident closures are also well known in the prior art for use on blow-molded milk containers and on fruit juice bottles. Illustrative of the prior art are U.S. Pat. Nos. 4,934,546, 4,844,268, 4,815,620, 4,589,561, 4,676,389, 4,676,389, 4,593,830, 4,699,268, 4,700,860, 4,202,455, 5,036,991, 3,940,004 and 4,066,182. Generally, these closures are shaped to engage the neck of a thin-walled blow molded plastic bottle used for milk, bottled water or juices. The neck of these bottles is typically formed with an inwardly turned flange at its upper end and includes an upper and lower external locking bead around the circumference of the neck to securely mate the closure thereto. Tamper evident closures of the prior art typically include a circular closure disk with a depending upper annular skirt and a lower depending annular skirt containing a tamper evident tear strip. Positioned on the internal walls of the respective skirt are upper and lower locking beads or flanges which are positioned to engage the external locking beads on the upper and lower portion of the neck of the bottle. Normally, the beads on the closure ride over the beads on the neck and provide "locking" of the closure on the container neck by the beads impeding sliding travel of the closure thereover. In addition, the prior art closures include a valve means depending from the inner surface of the closure disk which is adapted to engage the internal neck portion to create a seal at the mouth of the container. While the prior art snap-on closures provide evidence that a closure has been removed from the container when the tamper-evident band has been removed it is possible to remove many of the commercially available snap-on closures without removing the band. Moreover, when the tamper evident band having the lower locking bead has been removed, these caps do not provide a tight closure or effective seal. The removal of the lower skirt portion along with the tamper evidency deprives the cap of the primary locking means. This is typically not a problem with containers which are not reused, but with containers that are to be used or are not dispensed upon the initial opening the single remaining locking mechanism does not provide a leak proof seal.
Accordingly, it is an object of the present invention to provide a substantially leak proof tamper-evident closure combining a reusable, push-pull spout with a snap-on tamper evident closure which is substantially tamper proof.
Accordingly, it is an object of the present invention to provide an effective seal for a push-pull spout for reusable containers, combined with a snap-on tamper evident closure which provides a secure closure which is substantially tamper proof.
It is a further object of the present invention to provide a substantially leak proof push-pull pour spout for reusable containers, combined with a snap-on tamper evident closure having a first or upper locking means which provides additional locking forces when unauthorized removal is attempted.
It is a further object of the present invention to provide a substantially leak proof push-pull pour spout for reusable containers, combined with a snap-on tamper evident closure having an upturned internal locking flange to lock onto the upper locking bead of the container and having a push-pull resealable tamper evident pour spout.
It is a further object of the present invention to provide a substantially leak proof push-pull pour spout for reusable containers, combined with a snap-on tamper evident closure having a first locking member with a reverse internal flange which projects towards the mouth of the neck.
It is a further object of the present invention to provide a substantially leak proof push-pull pour spout for reusable containers, combined with a snap-on tamper evident closure that forms a secure seal upon reuse when the second skirt or tamper evident band is removed from the closure for reuse of the container.
It is a further object of the present invention to provide a snap-on tamper-evident closure with a reusable push-pull pour spout having a closure plug of increased structural flexibility to provide a more effective leak tight seal.
It is a further object of the present invention to provide a dimple means for facilitating the breakage of frangible elements on the tamper evident band of the push-pull pour spout closure.
It is a further object of the present invention to provide one or more continuous or discontinuous locking beads on the pour spout configured to engage one or more continuous or discontinuous locking beads on the pour spout closure to provide a structure for securing the pour spout closure to the pour spout the closed position and/or to prevent removal of the pour spout closure from the pour spout in the open position.
It is a further object of the present invention to provide a dust cover which encloses the push-pull pour spout closure when inserted on the container.
It is a further object of the present invention to provide a dust cover with a tamper-evident sealing band which encloses the push-pull pour spout closure when inserted on the container.
It is a further object of the present invention to eliminate the need for a band on the lower edge of the pour spout closure to provide tamper-evidency for the pour spout by providing a dust cover with a tamper-evident sealing band which encloses the push-pull pour spout closure when inserted on the container.
It is a further object of the present invention to provide a substantially leak proof push-pull pour spout for reusable containers, combined with a snap-on tamper evident closure which is usable on existing neck finishes with little or no modification.